Dental mandrel



ug. 19, 1924.` l. A. BURNETT DENTAL MANDREL Filed Nov. 1o. 1923 PatentedAug. 19, 1924.

UNITED STATES IRA A. BURNETT, yOF CHICAGO, ILLINOIS.

DENTAL MANDREL.

Application ledNovember 10, 1923.` "Serial No. 673,888.

To all whom t may concern: n

Be it known that I, IRA A. BURNETT, a citizen of the United States, anda resident of Chicago, county of Cook, and State; o-f Illinois, haveinvented certain new and useful Improvements in Dental Mandrels, ofwhich the following is a specification.

This invention relates to certain improvements in that class of dentaltoolsorr devices in which disks ofvarious kinds of material .used forgrinding, cutting, polishing, etc., are detachably securedto Shanks ormandrels adapted to be carried by a dentalengine hand-piece and drivenby a` flexible shaft connected with a dental-engine. A

The main. object of the invention `is the provision of a tool or mandrelof the above mentioned general character, which will positively holddisks of various kindsof material used by dentists, in such. a 'man themandrel and ineffective upon the reverse movement of the enginehand-piece, thereby overcoming this annoying difficulty, which alldentists have experienced, and furnishing a mandrel adapted for rotationin either v direction without the disk carried thereby becoming loose; yf j Other ob'ects and advantages of the invention will be disclosed inthe following description and explanation, which willbe more readilyunderstood when read in conjunction with the accompanyingdrawing, whichillustrates an embodiment of which the invention is susceptible, itbeingrunderstood that other arrangements and modifications mayberesorted to without departing from the spirit of the invention, solong as they come within the scope of the appended claims forming a parthereof.

In the accompanying4 drawing,-. y Fig. l is a greatly enlarged View ,inside elevation, of the tool or mandrel, showing a disk held thereby andthe parts of the device in their operative positions. j'

Fig. 2 is a central vertical sectional view of the upper portion of F 1.

Fig. 3 is a plan sectional viewtaken on line 3 3 of Fig. 2. v l y,

Fig. ,Il is a similar view taken on line Ae of Fig. 2-looking in thedirectionfin'dicated bythe arrows. V p- Fig. 5 is a detached View inrelevation of the detachable clamping vmember of the device.

Fig. 6 vis a view partly vin section and to a suitablefdistance, saidslotsbeing em-` ployed for weakening the `upper portion ofv partly inyelevation ofthe upper portion of the shank of the mandrel.

at which point the latter is provided witha collar 8 which is closely'fittedL to the shank `'but removable therefrom` and is remployed ytoact as afstop member for the controllingr nutpor member of thel device,asl will be presently explained. f i.

TheV shank Tis provided at.. its upper fend with an outwardly andupwardly tapered ,to any suitable distance, yet preferably to about thelongitudinal middle of the shank,

enlargement) the upper surface of whichk is by preferenceinwardlyinclined from its periphery as at l0, see Figs. 2and 6, for the purposeof providing a yrim to rest against t the lower surface of the disk `11to beheld rby the toolor mandrel. The outerfsurface ofthe enlargement9,. is smoothr or without screw-threads, as shown in thelast ynamedfiguresof the drawing. The upper endofy the shank 7 y is yprovided witha pair of slots l2 which are located kdiametrieally oppositey each otherand extendA from andy through the upper end ofthe'enlargement9downwardly the shankso asto afford` to saidy portion fa, 1

degree of resiliency in'order that thefparts on eac-hside of the slots12 may be pressed ,towards each other undercertain conditions.

below ,the *flower ends of the` slots-therein.

Located diametricallyopposite each other on each side of thejslots 12 inthe enlarged portion 9 of the shankfare a pair of pro-y jections 13whiclriny the presentl instance are shown as `pins rlocated intransverse openings inthe enlargement y9 and as kr:having their innerends extended slightly 1n- .y wardlyof the wallsofthebore in thesha'nk.l

However, these projections may be of other construction or otherwisesecured to the enlarged portion 9 but so as to yextend a slight distanceinto its opening to perform the function to be presently explained.

The enlargement 9 constitutes the lower andiixed clamping jaw or memberof the device and is adapted to rest or press against the lower surfaceof the disk 11 concentrically around the central opening 14 therein withwhich each of the disks is provided.

Extended through the opening 14 ofthe disk into the bore of the shank isa stem 15 extended centrally from the inner or lower face yof the otheror detachable clamping member 16 of the device. The stem 15 is providedwith screw-threads on its lower Iportion to engage the internal threadsof longitudinally extendedvgroove betweeny the shank 7, butit will beseen and understood by reference to Figs. 2 and 5, that the threads onthe stem 15 terminate at their upper ends a considerable distancebelowthe clampiii-g member 16 on said stem,

`and that just below the member 16 the stem 15 is provided withlongitudinaliy extended ribs 17 spaced in parallelism so as to provideeac-h pair ofsaid ribs, into which the inwardly extended portions oftheprojections 18 will` fit in such-a way-as to slightly engage said ribsbut not `so as vto vprevent the stem 15 being screwed down into the boreof the shank until the clamping member 16 rests "on the upper -or outersurface of the disk 11 35 with sufiiicient pressure yt-o hold the diskagainst rotation on the stem 15 between the detachable- 'and fixedclamping member-s.

Mounted on the externally screw-threaded portion of thesh'ank 7 in screwengagement therewith, is a 'controlling nut or4 member 18 which is bypreference milled yon its outer `surface and of the shape shown kin Fig.1

ofthe "'drawin'g. The lupper *end of the screwlthreadedopening in themenrber 18 is outwardly flared as at 19 and is of a size to fit aroundthe upwardly tapered enlargement 'or fixed clampingm'ember '9: when thememb'eror nut 18 is k'advanced'on the screw- `threaded portion of theshank suiiiciently 'for lsaid purpose, vwhen by causing `the nut 18 tobe advanced further towards the disk y11i, it isl evident that 'thedivi-ded upper portions of the'shank as well fas the divided portions ofthe enlargement 9, will y be forced 'slightly towards eachother, thuscausing `the projections 131 carried by the clamping member or part ,9to yengage theribs 1f? lso as to prevent.' .rotation of the stem 15 inl'either direction, nofmatter `which way the mandrel 'may'b'e'rot-at-ed. l `*From the foregoing and by reference to 'the drawing,it will be'readily understood and Icl-early seen that, assuming it isdesired to piace a-disk 11 Iin operative'position on the mandrel,andfassumin-g that the vdetachable y'ri rbt-hand type.

clamping member 16 hasibeen removed from the position shown in Figs. 1and 2 and that the controlling nut or member 18 has been retracted onthe shank sufliciently to release the inclined or flared walls 19 of theupper end of the opening in said member from `contact with the outwardlyiiared clamping rmember 9, it is manifest that a disk 11 having acentral opening 14 therein, can be placed on the stemr 15 of theclamping member 16 when said stem can be .inserted into thescrew-threaded opening of the shank and caused to assume about .theposition shown in Figs. 1 and 2 by turningthe clamping member 16 in theproper direction. j

Now, by advancing the controlling nut 18 on'the shank, it is obviousthat 4the contact of its upper end with* the iiared c-lamping member 9lwill cause the projections 13 to engage lthe ribbed surface of the stem15,

thus causing -thedisk 11 to be-securely clamped between the la-st namedclamping member and thedetachable member and in such a way thatloosening ofthe disk will be prevented. Y 'l Y lVhile I 'have shown theupper portion Jvof `'the shank 7 provided with a pair of slots,

yet itis obvious that one lor more slots can be employed to kfurnishresiliency 'to the upper v portion of the shank or weakening thereof sothat its upper p-'ortionmay be slightly compressed by the upwardmovement of the controlling nut.V Instead r'of employing a pair lofprojections 13, a single projection' lm'ountedon the mandrel before orafter it hasbeen connected tothe handpie'ce,"'as is obvious.

It will be understood that the external screw-threads on the' shank 7'are left-hand ones, while those onthe stem'l are of the aving thusfuliy `described' my'invention, what I claimas new and Ydesire to secureby vLetters Patentv is 1. A dental mandrel comprising. a shank havingone of its r`ends slot-ted and provided withfa longitudinally extendedvbore having Ascr'ewethreadfs,v Said'endA ofthe shank being provided"withY a slotted clamping member and carrying inwardly extended engaging'outersurface flared, lsere'vv-threads on'the shank below saidl member,another clamping' member having a' stem provided on itslo'wer portionwith screw-threads to engage the threads of said bore and above saidthreads with engaging means to co-act withthe first named engaging meansand adapted to cooperate with the first namedclampin member to clamp adisk between them, anc acontrolling nut mounted on the screw-threadedportion of the shank and cofoperating with the first named clampingmember to cause said stern to be locked against independent rotarymovement.

2. A dental mandrel comprising a `shank having one of its ends slottedand provided with a longitudinally extended bore having screw-threadstherein below its slotted portion, Said end of the shank being providedwith a slotted clamping member and carrying at least one inwardlyextended projection, said clamping member having its outer Surfaceflared, screw-threads on the shank below said member, another clampingmember having a stem provided on its lower portion with screw-threads toengage the threads of said bore and above vsaid threads with spacedmeans to co-act with the rst named engaging means and adapted to c0-operate with the irst named clamping mem.`

ber to clamp a disk between them, and a controlling nut mounted on thescrewthreaded portion of the shank and co-operating with the first namedclamping member to cause said stem to be locked against independentrotary movement.

3. A dental mandrel comprising a shank having one of its ends slottedand provided with a longitudinally extended boreghaving screw-threadsbelow the slotted portion of the shank only, said end of the shank beingprovided with a slotted clamping member for a disk, at least oneinwardly extended projection carried by said member, said clampingmember having its outer surface ared, screw-threads on the shank belowsaid member, another clamping `member having a stem provided on itslower portion with screw-threads to engage the threads of said bore'andabove Said threads with lon gitudinally disposed spaced ribs to co-actwith the said inwardly ext-ended projection and adapted to co-operatewith the first named clamping member to clamp a disk between them, and acontrolling nut mounted on the screwthreaded portion of the shank andhaving the Lipper end of its opening flared for co-operation with theiirst named clamping member to cause said stem to be locked againstindependent rotary movement.

inn n. BURNETT.

